package com.archerdu.commons.util;

import java.security.MessageDigest;

public class SHA256 {

    /**
     * 转换为十六进制
     * 
     * @param b
     * @return
     */
    private static String byteArrayToHexString(byte b[]) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++)
            resultSb.append(byteToHexString(b[i]));

        return resultSb.toString();
    }

    /**
     * 十六进制转换
     * 
     * @param b
     * @return
     */
    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n += 256;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    /**
     * 加密
     * 
     * @param origin
     * @return
     */
    public static String encrypt(String origin) {
        String resultString = null;
        try {
            resultString = new String(origin);
            MessageDigest md = MessageDigest.getInstance("SHA-256");

            resultString = byteArrayToHexString(md.digest(resultString.getBytes()));

        } catch (Exception exception) {
        }
        return resultString;
    }

    /**
     * 十六进制字符
     */
    private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d",
            "e", "f"                       };

    public static void main(String[] args) {
        System.out.println(SHA256.encrypt("admin"));
        System.out.println(SHA256.encrypt("admin").length());
    }
}
